Home appliance



NCV. 1961 w. J. LINSTROMBERG ETAL 3,008,307

HOME APPLIANCE Filed Nov; 4, 1959 INV EN TORS wlamdzn sz W T 3 008307 HOME APPLANCE William J. Linstromberg and William E. Richard, Evansville, End., assignors to Whirlpool Corporation, a corporation of Delaware Filed Nov. 4, 1959, Ser. No. %50,810 3 Claims. (CI. 452-340) This invention relates to automatic ice makers and particularly to means for preventing the freezing of water in a water line leading to the ice mold of an automatic ice maker.

This invention may =be considered an addition to the ice maker disclosed and claimed in the co-pending Linstromberg application Serial No. 790,557, filed February 2, 1959, and owned by the common assignee. Briefly, the co-pending application discloses an ice maker, in which a body of ice is formed in a fruSto-conical cavity of a freezing mold and when frozen is ejected therefrom to be co-llected in a suitable container. The ejection of the ice 'body is alfected by a spring-urged block which is cam operated to snap against a plunger defining the lower boundary of the cavity. The cam is rotated by a suitable drive motor so that the ejection cycle is aifected only after water delivered to the cavity is properly frozen therein. Immediately after the ejection of an ice body, a water supply valve is actuated to provide a measured amount of water into the mold cavity by means of a conduit.

The principal feature of the instant invention is the provision of a new and improved means for preventing the freezing of water in the water conduit supplying an automatic ice maker.

Earlier devices for automatically providing bodies of ice have used complicated and expensive methods in an attempt to prevent the freezing of Water in the water supply conduit leading to the ice mold. Some of these devices used diverters or drains in the water line, or electric resistance heater wires wrapped around the water conduit and energized at periodic intervals to maintain the conduit at above freezing temperatures.

In accordance with the present invention, there is provided a simple, practical and inexpensive means for preventing the formation of ice in a water line leading to the ice mold of an automatic ice maker. Specifically, a plastic conduit is provided which have a very low heat conductivity value to minimize the transmission of heat from outside a refrigerated space to inside the space. A thin metallic inner lining extending substantially the entire length of the conduit has a heat conductivity value considerably higher than that of the plastic conduit. Sufficient heat is transferred by means of the lining, first, from the water passing thereth-rough, and second, from the Warmer in let end to the outlet end, so that all of the interior of the conduit is maintained substantially free of ice -formations to allow water to flow therethrough. Thus, there is provided a means to maintain the water supply conduit of an automatic ice maker completely free of any ice which would block the conduit and prevent the Satisfaetory operation of the ice maker.

Other features and advantages of the invention will be apparent from the following description, taken in connection with the accompanying drawing, wherein FIGURE 1 is a partial view of an automatic ice maker within a refrigerator, incorporatin-g one embodiment of our invention; and

FIGURE 2 is a section taken 'along line II-II of FIG- URE 1.

As seen in the drawing, an ice maker -apparatus, generally designated 10, is provided with a freezing mold 11 having a trusto-Comical cavity 12 in which are frozen a plurality of ice bodies. Water is delivered to cavity 12 from a supply line 13 through a valve 14, valve outlet &08,307 Patenta& Nov. 14, 1961 line 15, through a conduit 16, and through 'a chute 17. The valve 14 is operated automatically to fill mold cavity 12 by means of a motor (not shown) which rotates a shaft 18. i Mounted on shefit 18 is a cam 19 which engages a cam follo wer block 20 attached to 'lever 21. Lever 21 is pivotally mounted from ice mold 11,' as more specifically described in the co-pending application. The mold 11 may be refrigerated by a refrigerant carrying evaporator tube 23 connected as a part of a conventional refriger-ation system (not shown). The temperature of evaporator tube 23 is such that water within mold cavity 12 is quickly frozen into ice. Fur-ther, compantment 24 is maintained at below freezing temperatures by means of an evaporator coil 25. It will be apparent that mold 11 may be provided with finned surfaces to provide cooling of the mo-ld by a forced stream of cold air as from evaporator coil 25.

Rotation of shaft 18 and cam 19 causes a gradual downward deection of the pivoted lever 21 which is under spring tension. Whenvthe high point26 of cam 19 moves beyond cam follower block 20, the block and lever 21 are allowed to fly immediately upwardly so that the lever strikes the lower end 27 of plunger 28. The curved upper end portion 29 of plunger 28 defines the lower end surface of mold cavity 12. The sudden striking ofplunger 28 by 'lever 21 causes the plunger to move quickly upwardly and eject the ice body upwardly from cavity 12.

Shbrtly after ice ejection, the water valve 14 is energized to provide a measured amount of water Via line 15, conduit 16 and chute 17. Line 15 is connected to water conduit '16 at an integral right-angle projecton 30 of the conduit. The purpose of this is to substantially reduce the pressure of the water to minimize the velocity of the stream of water passing through conduit 16. Should'water line 15 be connected in parallel with the longitudin-al axis of conduit 16, there may be sufficient velocity of the water stream to over-shoot the mold cavity 12. Because of the right-angle entrance, water falls substanti-ally by gravity down conduit 16 and chute 17 into mold cavity 12. To prevent swirling of the water within the conduit, there is provided a longitudinal inwardly projecting rib 31 extending substantially from inlet end 33 to outlet end 34 of conduit 16. Thus, the entry of the water at right angles to the longitudinal axis of the water conduit 16 and longitudinal rib 31 therein combine to provide a measured amount of water flowing through the conduit at a reduced velocity and with substantially no swirling motion.

Water conduit 16 is `formed of polyethylene plastic, or other suitable material having a low heat conductivity. This property is necessary in order that a 'amount of heat will be transferred from outside the refrigerator to inside compartment 24 which is held a-t a below-freezing temperature. Compartment 24 is encased by walls as indicated at 37.

On early experimental ice maker models, it was found that water conduit 16, when provided only as described above, would occasionally freeze closed at outlet end 34 adjacent the mold 11. Close investigation indicated that the conduit would not drain completely dry following each passage of water, and small water droplets would remain along the bottom of the inner surface of the outlet end of the conduit. Occasionally, water droplets or even water vapor would condense on the top of the inner surface of the conduit near the outlet end and would remain and become frozen. Obviously, this collection of frozen water would build up over a number of cycles, and completely close off outlet end 34 of conduit 16.

To prevent this freezing of water within conduit 16 a thin brass lining 38 was placed substantially from the inlet end 33 of the conduit to the outlet end 34 and circurnventing the inner diameter of the conduit, the ends of the lining being adjacent the longitudinalrb 31, as

best seen in -FIGURE 2. Brass lining 38, which is approxmately .003 inch thick, provides for the transmissionof a suificient amount of beat from the inlet end of the conduit to the ou tlet end, so that the interier of the conduit 16 is maintained substantally free of ice formation at all times. Further, the -lining, which hasa much lower surface tension than does the polyethylene Conduit, provides for easier drainingof the inclinedsconduit 16.

' Lining 38 actually performs a double function in maintaining the inner surface of conduit 16 substantially' free of ice formatons. First, part of the interier of Conduit 1 6 may remain at a temperature colder than freezing, and this could allow ice to build up 'at or near the outlet end, most likely at the top, during the period when no water flowing through the Conduit. A small quantity of water flow might not remove this ice accumulation. In the present invention, even though the quantity of water is such that only a shallow stream fiows along the bottom of Conduit 16, suficient heat is quickly transfer-red' from the water through the entire circnmference of lining 38 so that any accumulated ice may be quickly removed.

Secondly, since a quantity of water passing through i Conduit 16 'may be sufiiciently small so that not enough heat is available to completely' remove all of the accumulated ice, lining 38 is extended substantially completely from inlet end 33 to outlet end 34. This provides for the transfer of sufiicient additional heat from the substantially warmer inlet end, to maintain the interier of the conduit at sufiieiently high temperature so that passage of water may quckly remove all the -accumulated ice! 'Thus, the addition of an inner lining having high heat conductivity to a water supply Conduit purposely having low heat conductivity provides a novel device for maintairn'ng` the interiorsurface of the Conduit substantially free of ice underall conditions.

By way of example, the heat conductivity value of the polyethylene water Conduit may be approximately 2.3 B.t.u. in./hr. sq. ft. -F., and of the brass lining may be approximately 600 B.t.u. n./hr. sq. ft; F. Of course it will be apparent that other materials may be selected -for use as long as the relative difierential in heat conductivity values is maintained.

While we 'have shown and described one embodiment of our invention, it is to -be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departin-g `from the spirit and scope of the invention as dened in the appended claims.-

We claim:

l. In a refirigerator, walls defining a space, means for maintainin-g said space at sub-freezing temperatures, a heat insulating fluid Conduit having an inlet located outside of said space and an outlet located within said space, and a heat ccnducting liner within said conduit for keeping said outlet substantially free of ice, said lining being formed of thin metal and extending at least partially circumierentially and substantially from said inlet to said outlet.

2. A heatinsulating lquid conduit having an inlet connected to a source of liquid and an outlet located in a sub-freezing atrn osphere, means within said Conduit for keeping said'outlet substantially free of ice, said means comprising a heat conductng liner extending 'at least partially' cicumferentially within said Conduit and extending substantially from said inlet to said outlet, said lining being formed of a material having higher heat conductivity than that of said Conduit.

3. A liquid transporting heat nsulating condut having 'an inlet and an outlet, said conduit comprising; right angle entrance means to reduce velocity of liquid supplie'd thereto; -an inwardly projecting -rib to maintain substant'ally axial :flow of liquid passing therethrough, and a hea-t conducting liner therewithin to efiect the temperature of the outlet of said Conduit relative to the temperature of the inlet of said Conduit.

References' cited in the file of this patent UNITED STATES PATENTS France Aug. 3, 1950 

